In a liquid crystal display device, there is provided a TFT substrate in which pixel electrodes, thin film transistors (TFT) and the like are arranged in a matrix form. Further, a counter substrate is disposed opposite to the TFT substrate. In the counter substrate, color filters and the like are formed at locations corresponding to the pixel electrodes of the TFT substrate. Then, a liquid crystal is sandwiched between the TFT substrate and the counter substrate. Thus, the liquid crystal display device forms an image by controlling the transmittance of light of the liquid crystal molecules for each pixel.
Regarding the liquid crystal display device, there is a strong demand for reducing the overall size of the set itself and reducing the thickness of the liquid crystal display panel, with the size of the screen being fixed. In order to reduce the thickness of the liquid crystal display panel, the liquid crystal display panel is formed and thinned by polishing the outside.
The TFT substrate including pixel electrodes, TFT and the like, and the counter substrate including color filters, are glass substrates constituting the liquid crystal display device. The two glass substrates are standardized, for example, at a thickness of 0.5 mm or 0.7 mm. It is difficult to obtain glass substrates, other than such standardized substrates, from the market. In addition, very thin glass substrates have a problem in the production process in terms of mechanical strength and bending or deformation, which reduces the production yield. For this reason, the liquid crystal display panel is formed by the standardized glass substrates and is thinned by polishing the external surface of the liquid crystal display panel.
When the thickness of the liquid crystal display device is reduced, there is a problem of mechanical strength. If mechanical stress is applied to the display surface of the liquid crystal display panel, the liquid crystal display panel may be destroyed. In order to prevent this, a front window is attached to the side of the screen of the liquid crystal display panel when the liquid crystal display panel is mounted to a cellular phone set and the like.
In general, the front window is attached to the liquid crystal display panel with a UV curable resin. In order to improve design quality and image quality, as well as other improvements, a black border is printed around the front window. Ultraviolet light does not easily pass through the portion of the black border print, so that non-uniformity occurs in the UV curable resin.
Japanese Unexamined Publication No. 2009-192792 describes a method of curing the UV curable resin under the black border print by using the gradient the black border print, in order to eliminate the non-uniformity in the degree of curing of the UV curable resin. In other words, in Japanese Unexamined Publication No. 2009-192792, the area of the black border print is divided into two parts: one is the inner part where the color is light, and the other is the outer part where the color is deep. With this configuration, it is possible to prevent the stress in the curing of the resin.